Clearance unloader



June 1,1926. 1,587,015

' F. VAN D. LONGACRE CLEARANCE UNLOADER Filed Odt. 19, 1925 I "In HIS ATTOR Patented June 1, 1926.

UNITED STATES PATENT OFFICE.

FREDERICK VAN DUZER LONGACRE, OF YONKERS, NEW YORK, ASSIGNOR T INGER- SOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

Application filed October This invention relates to compressors, but more particularly to clearance unloaders,

and the primary object of the invention is to obtain clearance control for a compressor by means and devices which avoid using the available valve space.

To accomplish this object, one or more clearance chambers are located intermediate the cylinder and the discharge connection, and certain of the main discharge valves are adapted to perform the additional function of clearance control valves, as shown and claimed in my copending application Serial No. 63,308, filed October 19, 1925.

In accordance with the present invention, however, each of the said main discharge valves is a double valve and has connected thereto as a unitary structure an auxiliary valve which controls the communication between a clearance chamber and the discharge connection. By this means the unitary main and auxiliary valves alternately control communication between a clearance chamber, and the cylinder and the discharge connection, respectively.

Further objects of the invention will hereinafter appear, and to these ends the invention is shown in one of its preferred forms in the accompanying drawing, which is a diagrammatic longitudinal sectional elevation of so much of a compressor embodying the invention as will serve to make the invention clear.

Referring to the drawings, the cylinder A is provided with a reciprocating piston Band the usual water jacket C. The inlet D is controlled by the usual discharge valves E at each end of the cylinder and the compressed fluid is discharged at the discharge connection F. In this instance the compressor is shown as double acting, and clearance chambers G and H are located in the cylinder casing between the ends of the cylinder A and the discharge connection F.

Main discharge valves J and K are located in the valve openings L and 0 between the clearance chambers G and H and the ends of the cylinder, and auxiliary valves P and Q, connected to the main valves J and K form a unitary structure therewith and are adapted to control the valve openings R and S between the clearance chambers G and H and thedischarge connection F. As shown in this instance, the main dis- CLEARANOE UNLOADER.

19, 1925. Serial No. 113,309.

charge valve structures J and K seat against the seats T and U in the valve openings L and O in the cylinder and the auxiliary valve structures P and Q, seat against the valve seats V and W conveniently formed on valve cages X and Y within which the unitary valves operate. 1

The auxiliary valve P is shown of the plate type, while the auxiliary valve Q is shown as an ordinary disk, but suitable form of auxiliary valve may be used. When the main discharge valve J is bodily raised from its seat, as indicated in the drawing, the auxiliary valve structure P is seated in the opening R of the cage X and the plate valve functions as a discharge valve. When the main dischar e valve K at the opposite end of the cylin or is raised from its seat to render the valve inoperative, the valve disk Q, closes communication between the clearance chamber H and the discharge connec-.

tion F, but discharge at reduced pressure may still take place through additional main discharge valves (not shown) afiording com- 7 r munication between the cylinder and the discharge connection F.

Manual means are shown for raising and lowering the unitary valve structure J, P, in this instance a screw threaded stem Y having a handle or wheel Z being connected to the valve P, which in turn is connected to the valve J by means of the yoke a. The portion 6 of the cage X is screw threaded to receive the stem Y so that rotation of the stem raises and lowers the valve structures.

Instead of manual operating means, pressure fluid controlled means may be provided for raising and lowering the valve structures, and the valve K is shown provided with a yoke a connected to the valve disk Q which in turn is connected by the rod d to the piston 6 operating in the cylinder 7 and provided withthe pressure fluid connections 9 and h adapted to be controlled in any suitable manner, not shown. Movement of the piston e downwardly and inwardly lifts and lowers the unitary valve structure K, Q.

Either the manual or the pressure fluid acv Charge connection, a Clearance chamber intermediate the cylinder and said discharge connection, and a double discharge valve having a main valve and an auxiliary valve connected together as a unit and alternately controlling communication between the clearance chamber and the cylinder, and the clearance chamber and the discharge connection, respectively.

2. In a compressor, the combinationof a cylinder and piston, an inlet valve, a dis-' charge connection, a clearance chamber intermediate the cylinder and said discharge connection, a double discharge valve having a main valve and an auxiliary valve connected together as a unit and alternately controlling communication between the clearance chamber and the cylinder, and the clearance chamber and the discharge connection, respectively, and means for rendering the main Valve inoperative while'at the same time causing the auxiliary valve to close communication between the clearance chamber and the discharge connection.

In testimony whereof I have signed this specification.

FREDERICK vln DUZER LONGACRE. 

